Semiconductor device having package on package structure and method of manufacturing the semiconductor device

ABSTRACT

A semiconductor device having a package on package (PoP) structure, in which a fine pitch between package substrates is implemented, a total height of a package is reduced, and reliability is enhanced. The semiconductor package includes a first package substrate including a first body layer and a first passivation layer, a first semiconductor chip on the first package substrate, a second package substrate on the first package substrate, the second package substrate including a second body layer and a second passivation layer, a first connection member on the first package substrate outside the first semiconductor chip, and a gap filler filled between the first package substrate and the second package substrate, wherein the first package substrate includes a first trench, the second package substrate includes a second trench, and the first semiconductor chip is disposed between the first trench and the second trench.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority under 35 U.S.C. § 119 to Korean PatentApplication No. 10-2020-0170751, filed on Dec. 8, 2020, in the KoreanIntellectual Property Office, the disclosure of which is incorporated byreference herein in its entirety.

BACKGROUND

The inventive concept relates to a semiconductor package, and moreparticularly, to a semiconductor package having a package on package(PoP) structure and a method of manufacturing the semiconductor package.

As the electronic industry advances rapidly to meet the demands ofusers, electronic devices are being more and more miniaturized andlightweight. As electronic devices are miniaturized and lightweight,semiconductor packages are being miniaturized and made lightweight, andmoreover, need high performance, large capacity, and high reliability.For small, lightweight, high performance, large capacity, and highreliability electronic devices, semiconductor packages having a PoPstructure, where a package is disposed on another package, are beingcontinuously researched and developed.

SUMMARY

The inventive concept provides a semiconductor device having a packageon package (PoP) structure, in which a fine pitch between packagesubstrates is implemented, a total height of a package is reduced, andreliability is enhanced, and a method of manufacturing the semiconductorpackage.

According to an aspect of the inventive concept, there is provided asemiconductor device having a package on package (PoP) structure, thesemiconductor package including a first package substrate including afirst body layer and a first passivation layer on a top surface of thefirst body layer, a first semiconductor chip mounted on the firstpackage substrate, a second package substrate disposed on the firstpackage substrate and the first semiconductor chip, the second packagesubstrate including a second body layer and a second passivation layeron a bottom surface of the second body layer, first connection membersdisposed on the first package substrate outside the first semiconductorchip to electrically connect the first package substrate to the secondpackage substrate, and a gap filler filled between the first packagesubstrate and the second package substrate and surrounding at least someof portions of the first connection members. The first package substrateincludes a first trench formed by removing a center portion of the firstpassivation layer, the second package substrate includes a second trenchformed by removing a center portion of the second passivation layer, andthe first semiconductor chip is disposed between the first trench andthe second trench.

According to an aspect of the inventive concept, there is provided asemiconductor device having a package on package (PoP) structure, thesemiconductor device including a first package substrate including afirst body layer, a first upper passivation layer on a top surface ofthe first body layer, and a first lower passivation layer on a bottomsurface of the first body layer, and a first trench formed at a centerportion of the first upper passivation layer on the top surface of thefirst body layer, a second package substrate disposed on the firstpackage substrate, the second package substrate including a second bodylayer, a second upper passivation layer on a top surface of the secondbody layer, and a second lower passivation layer on a bottom surface ofthe second body layer, and a second trench formed at a center portion ofthe second lower passivation layer on the bottom surface of the secondbody layer, a first semiconductor chip mounted on a top surface of thefirst package substrate and disposed in a space between a first regionof the first package substrate where the first trench is formed and asecond region of the second package substrate where the second trench isformed, and an upper package mounted on a top surface of the secondpackage substrate, the upper package including a second semiconductorchip, an epoxy molding compound (EMC) covering the first semiconductorchip and filling at least a portion of each of the first trench and thesecond trench, and a gap filler including a material which differs fromthe EMC and filling at least a portion between the first upperpassivation layer of the first package substrate and the second lowerpassivation layer of the second package substrate.

According to an aspect of the inventive concept, there is provided amethod of manufacturing a semiconductor device having a package onpackage (PoP) structure, the method including preparing a first packagesubstrate and a second package substrate, forming a first trench at atop surface of the first package substrate and forming a second trenchat a bottom surface of the second package substrate, placing a firstsemiconductor chip on a first region of the first package substratewhere the first trench is formed, stacking the second package substrateon the first package substrate so that the first semiconductor chip isdisposed in a space between the first region of the first packagesubstrate and a second region of the second package substrate where thesecond trench is formed, sealing the first semiconductor chip using anepoxy molding compound (EMC), and mounting an upper package on thesecond package substrate. The stacking of the second package substrateon the first package substrate includes bonding the second packagesubstrate to the first package substrate by using first connectionmembers and a gap filler including a material which differs from theEMC.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the inventive concept will be more clearly understoodfrom the following detailed description taken in conjunction with theaccompanying drawings in which:

FIG. 1 is a cross-sectional view of a semiconductor package having apackage on package (PoP) structure according to an embodiment;

FIGS. 2A to 2C are a cross-sectional view, a perspective view, and aplan view illustrating a stack structure of package substrates and astructure of a package substrate, in the semiconductor package of FIG.1;

FIGS. 3A and 3B are a perspective view and a plan view illustrating astructure of a gap filler, in the semiconductor package of FIG. 1;

FIGS. 4A to 4C are plan views illustrating various embodiments of astructure of a gap filler, based on the semiconductor package of FIG. 1;

FIG. 5 is a cross-sectional view of a semiconductor package having a PoPstructure according to an embodiment;

FIGS. 6A to 8B are cross-sectional views, perspective views, and planviews illustrating semiconductor packages having a PoP structureaccording to embodiments;

FIGS. 9A to 9C are plan views illustrating various embodiments of astructure of a gap filler, in one of the semiconductor packages of FIGS.6A, 7A, and 8A;

FIG. 10 is a cross-sectional view of a semiconductor package having aPoP structure according to an embodiment; and

FIGS. 11A to 17 are cross-sectional views and a conceptual view simplyillustrating a method of manufacturing a semiconductor package having aPoP structure, according to an embodiment.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments will be described in detail with reference tothe accompanying drawings. Like numeral references refer to likeelements, and their repetitive descriptions are omitted.

FIG. 1 is a cross-sectional view of a semiconductor package having apackage on package (PoP) structure according to an embodiment, FIGS. 2Ato 2C are a cross-sectional view, a perspective view, and a plan viewillustrating a stack structure of package substrates and a structure ofa package substrate, in the semiconductor package of FIG. 1, and FIGS.3A and 3B are a perspective view and a plan view illustrating astructure of a gap filler, in the semiconductor package of FIG. 1.

Referring to FIGS. 1 to 3B, a semiconductor package having a PoPstructure (hereinafter simply referred to as a semiconductor package ora semiconductor device) 100 according to an embodiment may include afirst package substrate 110, a second package substrate 120, a firstsemiconductor chip 130, a first connection member 140, a gap filler 150,and an upper package 160.

The first package substrate 110 may be a supporting substrate of thesemiconductor package 100 and may include a first body layer 111, alower passivation layer 113 d, and an upper passivation layer 113 u. Thefirst body layer 111 may include a wiring of at least one layer therein.In a case where the wiring is formed of a multilayer, wirings ofdifferent layers may be connected to each other through a verticalcontact. According to an embodiment, the first body layer 111 mayinclude a through via which directly connects a substrate pad, disposedon a top surface thereof, to a substrate pad disposed on a bottomsurface thereof. The first body layer 111 may be formed based on, forexample, a ceramic substrate, a printed circuit board (PCB), a glasssubstrate, or an interposer substrate. According to an embodiment, thefirst body layer 111 may be formed based on an active wafer such as asilicon wafer. The first body layer 111 may have a first thickness D1.The first thickness D1 may be, for example, about 100 μm to about 200μm. However, the first thickness D1 is not limited to this numericalrange. Terms such as “about” or “approximately” may reflect amounts,sizes, orientations, or layouts that vary only in a small relativemanner, and/or in a way that does not significantly alter the operation,functionality, or structure of certain elements. For example, a rangefrom “about 0.1 to about 1” may encompass a range such as a 0%-5%deviation around 0.1 and a 0% to 5% deviation around 1, especially ifsuch deviation maintains the same effect as the listed range.

The lower passivation layer 113 d may be disposed on the bottom surfaceof the first body layer 111, and the upper passivation layer 113 u maybe disposed on the top surface of the first body layer 111. The lowerpassivation layer 113 d and the upper passivation layer 113 u mayinclude or may be formed of, for example, solder resist (SR). However, amaterial of each of the lower passivation layer 113 d and the upperpassivation layer 113 u is not limited to SR. Each of the lowerpassivation layer 113 d and the upper passivation layer 113 u may have asecond thickness D2. The second thickness D2 may be, for example, about10 μm to about 15 μm. However, the second thickness D2 is not limited tothis numerical range.

A substrate pad may be formed on each of the bottom surface and the topsurface of the first body layer 111, and a connection member may bedisposed on the substrate pad. For example, an external connectionmember 115 such as a bump or a solder ball may be disposed on the bottomsurface of the first body layer 111, and the first connection member 140may be disposed on the top surface of the first body layer 111. In FIG.1, although the external connection member 115 is illustrated as beingdisposed on the lower passivation layer 113 d, the external connectionmember 115 may be electrically connected to the substrate pad on thebottom surface of the first body layer 111 through the lower passivationlayer 113 d. The first connection member 140 will be described below inmore detail in describing the first connection member 140.

As seen in FIG. 2B, in the upper passivation layer 113 u, a centerportion thereof may be removed, and only an outer portion thereof may bemaintained (i.e., remain) on the top surface of the first body layer111. Based on a shape of the upper passivation layer 113 u, the firstpackage substrate 110 may include a first trench T1 in a top surfacethereof. The first trench T1 may be formed by removing part of the upperpassivation layer 113 u, and thus, a depth of the first trench T1 maycorrespond to the second thickness D2 of the upper passivation layer 113u. For reference, for convenience of illustration, the first connectionmember 140 is omitted in FIG. 2B, and the first connection member 140 isillustrated in FIG. 2C.

The first semiconductor chip 130 may be disposed in the first trench T1,and thus, a width of the first trench T1 may be one which enables thefirst trench T1 to sufficiently accommodate the first semiconductor chip130. For example, a width of the first trench T1 in a first direction(an x direction) and a width of the first trench T1 in a seconddirection (a y direction) may respectively be greater than a width ofthe first semiconductor chip 130 in the first direction (the xdirection) and a width of the first semiconductor chip 130 in the seconddirection (the y direction). In some embodiments, the firstsemiconductor chip 130 may be disposed on a region of the first packagesubstrate 110 where the first trench T1 is formed. Depending on a sizeof a third connection member 132 which is formed on a bottom surface ofthe first semiconductor chip 130, the bottom surface of the firstsemiconductor chip 130 may be lower or higher than a top surface of theupper passivation layer 113 u.

The second package substrate 120 may be a supporting substrate of theupper package 160 and may include a second body layer 121, a lowerpassivation layer 123 d, and an upper passivation layer 123 u. In thesemiconductor package 100 according to the present embodiment, thesecond package substrate 120 may be used for converting or transferringan input electrical signal between the first package substrate 110 andthe upper package 160. Therefore, the second package substrate 120 maynot include elements such as an active element or a passive element. Interms of an arrangement position and a function of the second packagesubstrate 120, the second package substrate 120 may be referred to as aninterposer. A PoP structure including an interposer may be referred toas an interposer PoP (iPoP).

The second body layer 121 may include or may be formed of, for example,one of silicon, an organic material, plastic, and glass. A material ofthe second body layer 121 is not limited to the materials. When thesecond body layer 121 includes or is formed of silicon, the secondpackage substrate 120 may be referred to as a silicon interposer. Forthe second body layer 121 including or being formed of an organicmaterial, the second package substrate 120 may be referred to as a panelinterposer. In some embodiments, the number of panel interposersmanufactured in a tetragonal disk including an organic material may begreater than the number of silicon interposers manufactured on onesilicon wafer. For the second body layer 121 including or being formedof glass, the second package substrate 120 may be referred to as a glassinterposer.

The second body layer 121 may include a wiring of at least one layertherein. In a case where the wiring is formed of a multilayer, wiringsof different layers may be connected to each other through a verticalcontact. According to an embodiment, the second body layer 121 mayinclude a through via which directly connects a substrate pad, disposedon a top surface thereof, to a substrate pad disposed on a bottomsurface thereof. According to an embodiment, the second body layer 121may have a structure where a wiring layer is disposed at a lower portionthereof and a through via is disposed at an upper portion thereof. Insuch a structure, the through via may connect a substrate pad, disposedon the top surface of the second body layer 121, to a wiring of a wiringlayer, and the wiring of the wiring layer may be connected to asubstrate pad on the bottom surface of the second body layer 121. Thesecond body layer 121 may have a third thickness D3. The third thicknessD3 may be, for example, about 80 μm to about 150 μm. However, the thirdthickness D3 is not limited to this numerical range.

The lower passivation layer 123 d may be disposed on the bottom surfaceof the second body layer 121, and the upper passivation layer 123 u maybe disposed on the top surface of the second body layer 121. The lowerpassivation layer 123 d and the upper passivation layer 123 u mayinclude or may be formed of, for example, SR. However, a material ofeach of the lower passivation layer 123 d and the upper passivationlayer 123 u is not limited to SR. The lower passivation layer 123 d andthe upper passivation layer 123 u may each have substantially the samethickness as that of each of the lower passivation layer 113 d and theupper passivation layer 113 u. For example, each of the lowerpassivation layer 123 d and the upper passivation layer 123 u may have asecond thickness D2 of about 10 μm to about 15 μm. However, the secondthickness D2 is not limited to this numerical range.

A substrate pad may be formed on each of the bottom surface and the topsurface of the second body layer 121, and a connection member may bedisposed on the substrate pad. For example, the first connection member140 may be disposed on the bottom surface of the second body layer 121,and a second connection member 162 may be disposed on the top surface ofthe second body layer 121. In FIG. 1, although the second connectionmember 162 is illustrated as being disposed on the upper passivationlayer 123 u, the second connection member 162 may be electricallyconnected to the substrate pad on the top surface of the second bodylayer 121 through the upper passivation layer 123 u.

The second package substrate 120 may include a second trench T2 in abottom surface thereof. The second trench T2 of the second packagesubstrate 120 may be formed by removing a center portion of the lowerpassivation layer 123 d. In FIG. 2B, the first trench T1 of the firstpackage substrate 110 is illustrated, and in a case where a bottomsurface of the second package substrate 120 is toward an upwarddirection, a shape of the second trench T2 of the second packagesubstrate 120 may be substantially the same as that of the first trenchT1 of the first package substrate 110. The second trench T2 may beformed by removing part of the lower passivation layer 123 d, and thus,a depth of the second trench T2 may correspond to the second thicknessD2 of the lower passivation layer 123 d. The second trench T2 may havesubstantially the same area as that of the first trench T1, andmoreover, may be formed in the bottom surface of the second body layer121 at a position facing the first trench T1 with the firstsemiconductor chip 130 therebetween. In some embodiment, the firstsemiconductor chip 130 may be disposed between a region of the firstpackage substrate 110 where the first trench T1 is formed and a regionof the second package substrate 120 wherein the second trench T2 isformed.

The first semiconductor chip 130 may be mounted on a top surface of thefirst package substrate 110. The first semiconductor chip 130 may be,for example, a logic chip. Here, the logic chip may include anapplication processor (AP), a microprocessor, a central processing unit(CPU), a controller, or an application specific integrated circuit(ASIC). The first semiconductor chip 130 may have a fourth thickness D4.The fourth thickness D4 may be, for example, about 50 μm to about 150μm. However, the fourth thickness D4 is not limited to this numericalrange.

As illustrated in FIGS. 1 to 2A, the first semiconductor chip 130 may bedisposed in the first trench T1 in the top surface of the first packagesubstrate 110. In some embodiment, the first semiconductor chip 130 maybe disposed on a region of the first package substrate 110 where thefirst trench T1 is formed. The first semiconductor chip 130 may beelectrically connected to the first package substrate 110 through athird connection member 132, and an underfill 134 may be filled betweenthe first semiconductor chip 130 and the first package substrate 110 andbetween third connection members 132. According to an embodiment,instead of the underfill 134, a first sealant 136 covering the firstsemiconductor chip 130 may be filled therein through a molded underfill(MUF) process.

The first semiconductor chip 130 may be sealed by the first sealant 136.The first sealant 136 may include or may be formed of, for example, aresin such as an epoxy molding compound (EMC). A material of the firstsealant 136 is not limited to the EMC. The first sealant 136 may fill atleast a portion of each of the first trench T1 and the second trench T2,cover a top surface and a side surface of the first semiconductor chip130, and cover the underfill 134. The first sealant 136 may have a fifththickness D5. The fifth thickness D5 may be, for example, about 100 μmto about 200 μm. However, the fifth thickness D5 is not limited to thisnumerical range.

A first gap G1 may be maintained between the first semiconductor chip130 and the second package substrate 120. For example, a top surface ofthe first semiconductor chip 130 and a bottom surface of the second bodylayer 121, which is exposed by the second trench T2, of the secondpackage substrate 120 may be spaced apart from each other at the firstgap G1. A portion corresponding to the first gap G1 may be filled by thefirst sealant 136. The first gap G1 may be maintained between the firstsemiconductor chip 130 and the second package substrate 120, and thefirst gap G1 may be filled by the first sealant 136, and thus, warpageof the semiconductor package 100 may be prevented. For example, thefirst sealant 136 may decrease stress caused by a difference in anexpansion rate (e.g., a thermal expansion coefficient) between the firstpackage substrate 110, the second package substrate 120, and the firstsemiconductor chip 130. The first gap G1 may have, for example, a sizeequal to the second thickness D2 corresponding to a depth of the secondtrench T2. However, a size of the first gap G1 is not limited thereto.For example, the first gap G1 may be maintained in an appropriate sizeon the basis of reduction in a height of the semiconductor package 100and the amount of warpage.

The first connection member 140 may be disposed between the firstpackage substrate 110 and the second package substrate 120 and mayelectrically connect the first package substrate 110 to the secondpackage substrate 120. As seen in FIG. 2C or 3B, the first connectionmember 140 may be disposed on the top surface of the first packagesubstrate 110 outside the first semiconductor chip 130 or the firsttrench T1. In terms of the second package substrate 120, the firstconnection member 140 may be disposed on the bottom surface of thesecond package substrate 120 outside the first semiconductor chip 130 orthe second trench T2.

The first connection member 140 may include a first pillar 141, a secondpillar 143, and a solder 145. The first pillar 141 may be connected tothe substrate pad on the top surface of the first package substrate 110,and the second pillar 143 may be connected to the substrate pad on thebottom surface of the second package substrate 120. Each of the firstpillar 141 and the second pillar 143 may have a cylindrical pillar or apolygonal pillar shape such as a tetragonal pillar shape or an octagonalpillar shape, which passes through a corresponding passivation layer ofthe first and second passivation layers 113 u and 123 d. Each of thefirst pillar 141 and the second pillar 143 may include or may be formedof, for example, nickel (Ni), copper (Cu), palladium (Pd), platinum(Pt), gold (Au), or a combination thereof. A material of each of thefirst pillar 141 and the second pillar 143 is not limited to thesematerials. In the semiconductor package 100 according to the presentembodiment, each of the first pillar 141 and the second pillar 143 mayinclude or may be formed of, for example, Cu.

The solder 145 may couple the first pillar 141 to the second pillar 143and may have a spherical shape or a ball shape. The solder 145 mayinclude or may be formed of, for example, tin (Sn), indium (In), bismuth(Bi), antimony (Sb), copper (Cu), silver (Ag), zinc (Zn), lead (Pb),and/or an alloy thereof. For example, the solder 145 may include or maybe formed of Sn, Pb, Sn—Pb, Sn—Ag, Sn—Au, Sn—Cu, Sn—Bi, Sn—Zn, Sn—Ag—Cu,Sn—Ag—Bi, Sn—Ag—Zn, Sn—Cu—Bi, Sn—Cu—Zn, or Sn—Bi—Zn. However, a materialof the solder 145 is not limited to these materials.

In the semiconductor package 100 according to the present embodiment, aplurality of first connection members 140 may be arranged at fine pitch.The plurality of first connection members 140 may be arranged at, forexample, a fine pitch of about 30 μm to about 50 μm. According to anembodiment, the plurality of first connection members 140 may bearranged at a fine pitch of about 10 μm to about 30 μm. A fine pitchbetween the first connection members 140 will be described in moredetail in describing an overall good characteristic of the semiconductorpackage 100 according to the present embodiment. A plurality of firstconnection members 140, as illustrated in FIGS. 2C and 3B, may bearranged in three columns at opposite sides in the first direction (thex direction) with the first semiconductor chip 130 therebetween and maybe arranged in one row at opposite sides in the second direction (the ydirection). However, the arrangement form of the first connectionmembers 140 is not limited thereto.

The gap filler 150 may be disposed between the first package substrate110 and the second package substrate 120 and between adjacent firstconnection members 140. The gap filler 150 may fill the second gap G2between the first package substrate 110 and the second package substrate120 at portions where the first connection members 140 are disposed.Here, the second gap G2 may correspond to a value obtained bysubtracting a sum of the first and second trenches T1 and T2 from thefifth thickness D5 of the first sealant 136. For example, the gap filler150 may fill a space between the upper passivation layer 113 u of thefirst package substrate 110 and the lower passivation layer 123 d of thesecond package substrate 120 and may surround at least some portions ofthe first connection members 140. The gap filler 150 may fill spacesbetween two adjacent first connection members 140.

As seen in FIGS. 3A and 3B, the gap filler 150 may be disposed on theupper passivation layer 113 u of the first package substrate 110 atopposite sides of the first semiconductor chip 130 or the first trenchT1 in the first direction (the x direction) and may extend in the seconddirection (the y direction). For example, the gap filler 150 may have arectangular shape, which is long in the second direction (the ydirection). However, a shape of the gap filler 150 is not limited to arectangular shape. Various shapes of the gap filler 150 will bedescribed below in more detail with reference to FIGS. 4A to 4C. Asillustrated in FIG. 2A or 3A, a width of the gap filler 150 in the firstdirection (the x direction) may be substantially the same as a width ofthe upper passivation layer 113 u in the first direction (the xdirection), at opposite sides of the first trench T1 in the firstdirection (the x direction). However, according to an embodiment, awidth of the gap filler 150 in the first direction (the x direction) maybe less than a width of the upper passivation layer 113 u in the firstdirection (the x direction).

For reference, for convenience of illustration, the first connectionmember 140 is omitted in FIG. 3A, and the first connection member 140 isillustrated in FIG. 3B. The gap filler 150 is illustrated as beingdisposed on the upper passivation layer 113 u of the first packagesubstrate 110, and according to some embodiments, the gap filler 150 maybe illustrated as being disposed on the lower passivation layer 123 d ofthe second package substrate 120.

The gap filler 150 may not be disposed on the upper passivation layer113 u of each of opposite end portions of the first package substrate110, outside the first semiconductor chip 130 or the first trench T1 inthe second direction (the y direction). Therefore, the opposite endportions of the first package substrate 110 may maintain an empty space.Each of the opposite end portions of the first package substrate 110 inthe second direction may act as an injection path IP through which thefirst sealant 136 is injected. For example, the first semiconductor chip130 may be mounted on the first package substrate 110 and the secondpackage substrate 120 may be stacked on the first package substrate 110through the first connection member 140 and the gap filler 150, andthen, the first sealant 136 may seal the first semiconductor chip 130 byinjecting the first sealant 136, such as an EMC, through the injectionpath IP of each of the opposite end portions of the first packagesubstrate 110 in the second direction.

The gap filler 150 may include or may be formed of a material whichdiffers from that of the first sealant 136. For example, the gap filler150 may include or may be formed of a nonconductive film (NCF), anonconductive paste (NCP), or SR. However, a material of the gap filler150 is not limited thereto. The gap filler 150 may be formed prior toforming the first sealant 136. For example, an upper connection memberof the first package substrate 110 and a lower connection member of thesecond package substrate 120 may be formed, and then, the gap filler 150may be formed to cover a corresponding connection member in one of thefirst package substrate 110 and the second package substrate 120. Here,the upper connection member may include the first pillar 141, and thelower connection member may include the second pillar 143 and the solder145. However, according to an embodiment, instead of the lowerconnection member, the upper connection member may include a solder, oreach of the lower connection member and the upper connection member mayinclude a solder.

The gap filler 150 may perform the following function as well as afunction of filling a region between the first package substrate 110 andthe second package substrate 120 to support the first package substrate110 and the second package substrate 120. First, in a case where thesecond package substrate 120 is stacked on the first package substrate110 through a temperature compression bonding (TCB) process, the gapfiller 150 may prevent a short circuit between the first connectionmembers 140. Here, the TCB process may denote that the second packagesubstrate 120 is stacked on the first package substrate 110 by applyingcertain pressure thereto at a high temperature (for example, about 200°C. to about 300° C.). Through the TCB process, the upper connectionmember of the first package substrate 110 may be coupled to the lowerconnection member of the second package substrate 120, and thus, thefirst connection member 140 may be formed. In the TCB process, a soldermay flow with fluidity on the basis of melting (i.e., the molten soldermay be flowable), and thus, may contact an adjacent solder, causingdefects such as a short circuit, deformation, and non-wetting. Here,non-wetting may denote that a solder is separated from a pillar, and anopen defect may occur due to non-wetting. However, in the semiconductorpackage 100 according to the present embodiment, the gap filler 150 maybe previously disposed on the upper connection member or the lowerconnection member, and thus, the flow of the solder 145 may be minimizedin the TCB process, thereby preventing defects such as a short circuit,solder deformation, and non-wetting. It will be understood that when anelement is referred to as being “connected” or “coupled” to or “on”another element, it can be directly connected or coupled to or on theother element or intervening elements may be present. In contrast, whenan element is referred to as being “directly connected” or “directlycoupled” to another element, or as “contacting” or “in contact with”another element, there are no intervening elements present. Other wordsused to describe the relationship between elements should be interpretedin a like fashion (e.g., “between” versus “directly between,” “adjacent”versus “directly adjacent,” etc.).

Subsequently, in a process of injecting the first sealant 136 to sealthe first semiconductor chip 130, the gap filler 150 may prevent a shortcircuit, solder deformation, and non-wetting from occurring in the firstconnection members 140 due to the penetration of the first sealant 136(i.e., flow of the first sealant 136) into a region between the firstconnection members 140. In a process of injecting the first sealant 136,the first sealant 136 may maintain a high temperature (e.g., atemperature above the melting temperature of the first sealant 136) sothat the first sealant 136 is injected with fluidity. In a case wherethe first sealant 136 having a high temperature penetrates or flows intospaces between the first connection members 140, flow based on meltingof a solder may occur, and due to this, a defect such as a shortcircuit, solder deformation, or non-wetting may occur in the firstconnection members 140. However, in the semiconductor package 100according to the present embodiment, the gap filler 150 may previouslyfill a region between the first connection members 140, and thus, thefirst sealant 136 may not penetrate the spaces between the firstconnection members 140, thereby avoiding the problems described above.The first trench T1 of the first package substrate 110 and the secondtrench T2 of the second package substrate 120 may perform a functionlike a dam which blocks flow of the first sealant 136, and thus, maymore effectively prevent the first sealant 136 from penetrating orflowing into spaces between the first connection members 140, along withthe gap filler 150.

For reference, as described above, the gap filler 150 may not bedisposed at the opposite end portions of the first package substrate 110in the second direction. However, as illustrated in FIG. 2C or 3B, thefirst connection members 140 of one row may be disposed at the oppositeend portions of the first package substrate 110 in the first direction,and thus, defects of the first connection members 140 caused by theinjection of the first sealant 136 may be minimized. For example,defects of the first connection members 140 caused by the injection ofthe first sealant 136 may occur in a direction (e.g., in the seconddirection) in which the first sealant 136 flows. However, the firstconnection members 140 of one row may be disposed at the opposite endportions of the first package substrate 110 in the first direction, andas seen through the arrow of the injection path IP of FIG. 3A, the firstsealant 136 may be injected to be vertical to a direction (e.g., in thefirst direction) in which the first connection members 140 are arranged,thereby minimizing defects of the first connection members 140 caused bythe penetration of the first sealant 136.

The upper package 160 may be mounted on the second package substrate 120by using the second connection member 162. The upper package 160 mayinclude an upper substrate 161, a chip stack portion 163, a thirdconnection member 165, and a second sealant 169.

The upper substrate 161 may include a wiring substrate, and thus, mayhave a structure similar to that of the first package substrate 110. Theupper substrate 161 may be formed to have a size and a thickness, whichare less than those of the first package substrate 110. According to anembodiment, the upper substrate 161 may be formed based on an activewafer such as a silicon wafer.

The chip stack portion 163 may be stacked on the upper substrate 161 byusing the third connection member 165 and may include at least onesecond semiconductor chip. In the semiconductor package 100 according tothe present embodiment, the chip stack portion 163 may include foursecond semiconductor chips 163 c. However, the number of secondsemiconductor chips of the chip stack portion 163 is not limitedthereto. For example, the chip stack portion 163 may include one tothree or five or more second semiconductor chips. The secondsemiconductor chip 163 c may include a volatile memory semiconductorchip, such as dynamic random access memory (DRAM) or static randomaccess memory (SRAM), or a non-volatile memory chip such as flashmemory, phase-change random access memory (PRAM), magnetoresistiverandom access memory (MRAM), ferroelectric random access memory (FeRAM),or resistive random access memory (RRAM). In the semiconductor package100 according to the present embodiment, the second semiconductor chip163 c may include a DRAM chip.

The second semiconductor chip 163 c may be stacked on a secondsemiconductor chip 163 c of a corresponding lower portion through anadhesive layer 163 p. A second semiconductor chip 163 c of a lowermostportion may be stacked on the upper substrate 161 through the thirdconnection member 165 and the underfill 167. According to an embodiment,instead of the underfill 167, the adhesive layer 163 p may be disposedbetween the upper substrate 161 and the lowermost second semiconductorchip 163 c. Although not shown, the second semiconductor chip 163 c mayinclude a through silicon via (TSV), except for the uppermost secondsemiconductor chip 163 c. Therefore, the second semiconductor chip 163 cmay be electrically connected to the upper substrate 161 or a secondsemiconductor chip 163 c of a corresponding lower portion through theTSV, a bump, and the third connection member 165. The adhesive layer 163p may surround a bump between adjacent second semiconductor chips 163 c.

According to an embodiment, the upper package 160 may have a structurewhere at least one second semiconductor chip 163 c is mounted on theupper substrate 161 through a wire bonding structure. In a case wherethe upper package 160 has such a structure, the third connection member165 may not be disposed between the upper substrate 161 and the secondsemiconductor chip 163 c of the lowermost portion. The secondsemiconductor chip 163 c may not include a TSV. The second semiconductorchip 163 c may be electrically connected to the upper substrate 161through a bonding wire, and the adhesive layer 163 p may attach thesecond semiconductor chip 163 c to the upper substrate 161 and mayattach each second semiconductor chip 163 c to a corresponding secondsemiconductor chip 163 c. Furthermore, in the wire bonding structure, aplurality of second semiconductor chips 163 c may be stacked in astaircase structure or a zigzag structure.

The second sealant 169 may cover a side surface and a top surface of thechip stack portion 163 on the upper substrate 161. The second sealant169 may cover a side surface of the underfill 167. According to anembodiment, the second sealant 169 may not cover a top surface of thechip stack portion 163, for example, a top surface of the uppermostsecond semiconductor chip 163 c of the chip stack portion 163.Therefore, the top surface of the uppermost second semiconductor chip163 c may be externally exposed from the second sealant 169. The secondsealant 169 may include or may be formed of, for example, an EMC.However, a material of the second sealant 169 is not limited to the EMC.

In the semiconductor package 100 according to the present embodiment,the first semiconductor chip 130 may be disposed between the first andsecond trenches T1 and T2 formed in the first and second packagesubstrates 110 and 120, and the gap filler 150 including or being formedof a material which differs from that of the first sealant 136 maysurround the first connection member 140 between the first and secondpackage substrates 110 and 120 to implement a fine pitch of the firstconnection members 140 and to decrease a total height of a package. Inthe semiconductor package 100 according to the present embodiment, adefect such as a short circuit, solder deformation, or non-wetting inthe first connection member 140 may be prevented by the gap filler 150.Accordingly, a semiconductor package having a PoP structure withenhanced reliability may be implemented.

To provide a more detailed description on a fine pitch of the firstconnection member 140 in the semiconductor package 100 according to thepresent embodiment, a pitch of connection members connecting packagesubstrates may be adjusted based on a size of a gap between the packagesubstrates and a structure of the connection member. For example, when agap between package substrates is relatively large and a connectionmember includes only a solder, a pitch of the connection members may bebased on an aspect ratio and a size of the solder. For example, in orderto prevent a short circuit defect between connection members and preventan open defect caused by non-wetting, an aspect ratio and a size of asolder have to be ensured, and thus, there is a limitation in decreasinga pitch of connection members.

On the other hand, in the semiconductor package 100 according to thepresent embodiment, the first and second trenches T1 and T2 may beformed in the first and second package substrates 110 and 120 and thefirst semiconductor chip 130 may be disposed between the first andsecond trenches T1 and T2, and thus, a gap (e.g., the shortest distance)between the first and second package substrates 110 and 120 may decreaseby a sum of depths of the first and second trenches T1 and T2 at aregion where the first semiconductor chip 130 is disposed. For example,when a gap between conventional package substrates including no trenchis about 100 μm to about 200 μm and a depth of each of the first andsecond trenches T1 and T2 of the first and second package substrates 110and 120 is about 10 μm to about 15 μm, a gap (the shortest distance)between the first and second package substrates 110 and 120 may be 70 μmto 180 μm, which corresponds to a size obtained by decreasing 100 μm to200 μm by 20 μm to 30 μm. The gap between the first and second packagesubstrates 110 and 120 may correspond to a distance between a topsurface of the upper passivation layer 113 u of the first packagesubstrate 110 and a bottom surface of the lower passivation layer 123 dof the second package substrate 120.

In the semiconductor package 100 according to the present embodiment,the first connection member 140 may have a structure including the firstand second pillars 141 and 143 and the solder 145, and the gap filler150 may be filled in spaces between the first connection members 140.Therefore, comparing a structure of a conventional connection memberincluding only a solder, defective problems of a short circuit andnon-wetting may be considerably reduced. Here, as described above, ashort circuit and non-wetting may occur in a process of stacking thesecond package substrate 120 and a process of injecting the firstsealant 136. As a result, in the semiconductor package 100 according tothe present embodiment, the first connection members 140 may be disposedto have the fine pitch described above on the basis of the reduction ina gap between the first and second package substrates 110 and 120, astructure of the first connection member 140, and the presence of thegap filler 150.

A total height of the semiconductor package 100 may decrease by a depthof a sum of the first and second trenches T1 and T2. For example, whenthe depth of each of the first and second trenches T1 and T2 is about 10μm to about 15 μm, the total height of the semiconductor package 100 maydecrease by about 20 μm to about 30 μm, which is a sum of the first andsecond trenches T1 and T2.

FIGS. 4A to 4C are plan views illustrating various embodiments of astructure of a gap filler, based on the semiconductor package of FIG. 1Descriptions, which are the same as or similar to descriptions givenabove with reference to FIGS. 1 to 3B, are briefly given below oromitted.

Referring to FIG. 4A, in a structure of a gap filler 150 a, asemiconductor package 100 a according to the present embodiment maydiffer from the semiconductor package 100 of FIG. 1. For example, in thesemiconductor package 100 a according to the present embodiment, a widthin a first direction (e.g., an x direction) of opposite end portions ofthe gap filler 150 a in a second direction (e.g., a y direction) may begreater than a width in the first direction of the central portions ofthe gap filler 150 a in the second direction. For example, the gapfiller 150 a may have a ‘[’-shape or a recessed portion at the centralportions in the second direction. A gap between the gap fillers 150 a inthe first direction (e.g., the x direction) at a portion correspondingto an injection path IP (e.g., at the opposite end portions of the gapfiller 150 a) may be narrower than a gap between the gap fillers 150 ain the first direction at the central portions or a width of a firsttrench T1 in the first direction (the x direction). A width, in thefirst direction (e.g., the x direction), of the gap filler 150 a at theopposite end portions thereof in the second direction (e.g., the ydirection) may be greater than a width, in the first direction, of thegap filler 150 a at the central portions thereof in the seconddirection, and thus, the gap filler 150 a at the opposite end portionsthereof may surround and protect more first connection members 140,thereby decreasing defects such as a short circuit, solder deformation,and non-wetting of the first connection members 140.

Referring to FIG. 4B, in a structure of a gap filler 150 b, asemiconductor package 100 b according to the present embodiment maydiffer from the semiconductor package 100 of FIG. 1. For example, in thesemiconductor package 100 b according to the present embodiment, a widthin a first direction (an x direction) in one end portion of the gapfiller 150 b in a second direction (a y direction) may be greater than awidth of another portion thereof. For example, the gap filler 150 b mayhave a ‘L’-shape. Based on such a structure of the gap filler 150 b, ina portion corresponding to an injection path IP, a gap between the gapfillers 150 b in the first direction (e.g., the x direction) may benarrower than a width of a first trench T1 in the first direction (e.g.,the x direction). A width of the gap filler 150 b at the one end portionthereof (for example, the end portion corresponding to the injectionpath IP) in the second direction (the y direction) may be greater than awidth of the gap filler 150 b at the other portions in the seconddirection, and thus, the gap filler 150 b may surround and protect morefirst connection members 140, thereby decreasing defects such as a shortcircuit, solder deformation, and non-wetting of the first connectionmembers 140.

Referring to FIG. 4C, in a structure of a gap filler 150 c, asemiconductor package 100 c according to the present embodiment maydiffer from the semiconductor package 100 of FIG. 1. For example, in thesemiconductor package 100 c according to the present embodiment, the gapfiller 150 c may be disposed on an upper passivation layer 113 u of afirst package substrate 110 at opposite sides of a first semiconductorchip 130 or a first trench T1 in a first direction (e.g., an xdirection), and may be disposed in a lattice shape between a pluralityof first connection members 140. For example, it may be seen that thefirst connection members 140 are disposed between adjacent portions ofthe gap filler 150 c having a lattice shape. As illustrated, the gapfiller 150 c may not be disposed at a portion corresponding to aninjection path IP.

The gap filler 150 c having a lattice shape may include or may be formedof NCP. For example, the gap filler 150 c may be formed by dispensingNCP into spaces between the first connection members 140 in a latticeshape by using a dispenser. In a process of stacking the second packagesubstrate 120 and a process of injecting a first sealant 136, the gapfiller 150 c having a lattice shape may surround and protect the firstconnection members 140, thereby preventing defects such as a shortcircuit, solder deformation, and non-wetting of the first connectionmembers 140.

FIG. 5 is a cross-sectional view of a semiconductor package 100 d havinga PoP structure according to an embodiment. Descriptions, which are thesame as or similar to descriptions given above with reference to FIGS. 1to 3B, are briefly given below or omitted.

Referring to FIG. 5, in a structure of a first connection member 140 a,the semiconductor package 100 d according to the present embodiment maydiffer from the semiconductor package 100 of FIG. 1. For example, in thesemiconductor package 100 d according to the present embodiment, thefirst connection member 140 a may include only a solder. In thesemiconductor package 100 d according to the present embodiment, a gapfiller 150 may fill in spaces between two adjacent first connectionmembers of a plurality of first connection members 140 a, and thus,although the first connection member 140 a includes only a solder,defects such as a short circuit, solder deformation, and non-wetting ofthe first connection members 140 a may be prevented in a process ofstacking a second package substrate 120 and a process of injecting afirst sealant 136.

In FIG. 5, the first connection member 140 a may have a soldersingle-layer structure including or being formed of one solder, butaccording to embodiments, the first connection member 140 a may includeor may be formed of a solder multi-layer structure where a plurality ofsolders are stacked. As shown in FIG. 3A, the gap filler 150 may have arectangular shape which is long in a second direction (e.g., a ydirection). However, the gap filler 150 is not limited thereto and mayhave a shape of one of the gap fillers 150 a to 150 c of FIGS. 4A to 4C.

FIGS. 6A to 8B are cross-sectional views, perspective views, and planviews illustrating semiconductor packages having a PoP structureaccording to embodiments. FIGS. 6B, 7B, and 8B are perspective viewsillustrating a structure of a gap filler in semiconductor packages ofFIGS. 6A, 7A, and 8A, and FIG. 6C is a plan view illustrating astructure of a gap filler in the semiconductor package of FIG. 6A.Descriptions, which are the same as or similar to descriptions givenabove with reference to FIGS. 1 to 3B, are briefly given below oromitted.

Referring to FIGS. 6A to 6C, in a structure of each of an upperpassivation layer of a first package substrate 110 a and a lowerpassivation layer of a second package substrate 120 a, a semiconductorpackage 100 e according to the present embodiment may differ from thesemiconductor package 100 of FIG. 1. For example, in the semiconductorpackage 100 e according to the present embodiment, the first packagesubstrate 110 a may include a first upper passivation layer 113 u-1 anda second upper passivation layer 113 u-2 on a top surface of a firstbody layer 111, and the second package substrate 120 a may include afirst lower passivation layer 123 d-1 and a second lower passivationlayer 123 d-2 on a bottom surface of a second body layer 121. The firstupper passivation layer 113 u-1, the second upper passivation layer 113u-2, the first lower passivation layer 123 d-1, and the second lowerpassivation layer 123 d-2 may each include or may be formed of SR.However, a material of each of the first and second upper passivationlayers 113 u-1 and 113 u-2 and the first and second lower passivationlayers 123 d-1 and 123 d-2 is not limited to SR.

A first trench T1 of the first package substrate 110 a may be formed byremoving a center portion of each of the first upper passivation layer113 u-1 and the second upper passivation layer 113 u-2. In someembodiments, the first body layer 111 may be exposed via the firsttrench T1 of the first package substrate 110 a. A second trench T2 ofthe second package substrate 120 a may be formed by removing a centerportion of each of the first lower passivation layer 123 d-1 and thesecond lower passivation layer 123 d-2. In some embodiments, the secondbody layer 121 may be exposed via the second trench T2 of the secondpackage substrate 120 a. The first trench T1 and the second trench T2may each have an area which enables the first semiconductor chip 130 tobe accommodated thereinto. For example, the area of each of the firstand second trenches T1 and T2 may be greater than that of the firstsemiconductor chip 130.

In the semiconductor package 100 e according to the present embodiment,the second upper passivation layer 113 u-2 and the second lowerpassivation layer 123 d-2 may perform a function of a gap filler. Forexample, the second upper passivation layer 113 u-2 and the second lowerpassivation layer 123 d-2 may be referred to as a gap filler. Asillustrated in FIG. 6B, the second upper passivation layer 113 u-2 mayhave a rectangular shape which is long in a second direction (e.g., a ydirection), on the first upper passivation layer 113 u-1. Widths of thesecond upper passivation layer 113 u-2 and the first upper passivationlayer 113 u-1 in a first direction (an x direction) may be substantiallythe same, at opposite sides of the first trench T1 in the firstdirection (e.g., the x direction). However, according to an embodiment,a width of the second upper passivation layer 113 u-2 in the firstdirection (the x direction) may be less than that of the first upperpassivation layer 113 u-1 in the first direction (the x direction).Although not shown, the second lower passivation layer 123 d-2 may havesubstantially the same structure as that of the second upper passivationlayer 113 u-2. Terms such as “same,” “equal,” “planar,” or “coplanar,”as used herein when referring to orientation, layout, location, shapes,sizes, amounts, or other measures do not necessarily mean an exactlyidentical orientation, layout, location, shape, size, amount, or othermeasure, but are intended to encompass nearly identical orientation,layout, location, shapes, sizes, amounts, or other measures withinacceptable variations that may occur, for example, due to manufacturingprocesses. The term “substantially” may be used herein to emphasize thismeaning, unless the context or other statements indicate otherwise. Forexample, items described as “substantially the same,” “substantiallyequal,” or “substantially planar,” may be exactly the same, equal, orplanar, or may be the same, equal, or planar within acceptablevariations that may occur, for example, due to manufacturing processes.

According to embodiments, an upper passivation layer of the firstpackage substrate 110 a and a lower passivation layer of the secondpackage substrate 120 a may each have a multi-layer structure of threeor more layers. In a case where the upper passivation layer of the firstpackage substrate 110 a and the lower passivation layer of the secondpackage substrate 120 a each have a multi-layer structure of three ormore layers, the first trench T1 and the second trench T2 may be formedby removing all of such multilayer, or may be formed by removing aportion of the multilayer. Some of upper layers of a multilayer mayperform a function of a gap filler.

Furthermore, without a gap filler, the upper passivation layer of thefirst package substrate 110 a and the lower passivation layer of thesecond package substrate 120 a each have a single-layer structure. Insuch a structure, the upper passivation layer and the lower passivationlayer may be formed to have a thickness, which is sufficient to cover athickness of a gap filler, and an upper portion of at least one of theupper passivation layer and the lower passivation layer may perform afunction of a gap filler.

Referring to FIGS. 7A and 7B, in a semiconductor package 100 f accordingto the present embodiment, a second trench may not separately be formed,and thus, the semiconductor package 100 f according to the presentembodiment may differ from the semiconductor package 100 e of FIG. 6A.For example, in the semiconductor package 100 f according to the presentembodiment, the first package substrate 110 a may include a first upperpassivation layer 113 u-1 and a second upper passivation layer 113 u-2on a top surface of a first body layer 111, and the second packagesubstrate 120 a may include a first lower passivation layer 123 d-1 aand a second lower passivation layer 123 d-2 on a bottom surface of asecond body layer 121.

The first trench T1 of the first package substrate 110 a, like the firstpackage substrate 110 a of FIG. 6A, may be formed by removing a centerportion of each of the first upper passivation layer 113 u-1 and thesecond upper passivation layer 113 u-2. The first trench T1 may have anarea which enables the first semiconductor chip 130 to be accommodatedthereinto. However, as illustrated in FIG. 7B, a separate trench may notbe formed in the second package substrate 120 b. Therefore, the firstlower passivation layer 123 d-1 a may be formed on a whole bottomsurface of the second body layer 121 of the second package substrate 120b. In the semiconductor package 100 f according to the presentembodiment, the second upper passivation layer 113 u-2 of the firstpackage substrate 110 a and the second lower passivation layer 123 d-2of the second package substrate 120 b may perform a function of a gapfiller and may have a rectangular shape, which is long in the seconddirection (e.g., the y direction). For example, the second lowerpassivation layer 123 d-2 may be disposed in a rectangular shape, whichis long in the second direction (the y direction), on opposite outerportions of the first lower passivation layer 123 d-1 a in a firstdirection (e.g., an x direction).

Referring to FIGS. 8A and 8B, in a structure of each of an upperpassivation layer of a first package substrate 110 a, a semiconductorpackage 100 g according to the present embodiment may differ from thesemiconductor package 100 of FIG. 1. For example, in the semiconductorpackage 100 g according to the present embodiment, the second packagesubstrate 120 may be substantially the same as the second packagesubstrate 120 of the semiconductor package 100 of FIG. 1. Therefore, thesecond package substrate 120 may include a lower passivation layer 123 don a bottom surface of a second body layer 121.

In the semiconductor package 100 g according to the present embodiment,like the semiconductor package 100 e of FIG. 6A, the first packagesubstrate 110 c may include a first upper passivation layer 113 u-1 aand a second upper passivation layer 113 u-2 a on a top surface of thefirst body layer 111. However, a thickness of each of the first upperpassivation layer 113 u-1 a and the second upper passivation layer 113u-2 a may be thicker than that of each of the first upper passivationlayer 113 u-1 and the second upper passivation layer 113 u-2 of thefirst package substrate 110 a of the semiconductor package 100 e of FIG.6A. For example, a sum of the thicknesses of the first upper passivationlayer 113 u-1 a and the second upper passivation layer 113 u-2 a may besubstantially the same as a sum of thicknesses of the gap filler 150 andthe upper passivation layer 113 u of the semiconductor package 100 ofFIG. 1.

A first trench T1 of the first package substrate 110 c may be formed byremoving a center portion of each of the first upper passivation layer113 u-1 a and the second upper passivation layer 113 u-2 a. A secondtrench T2 of the second package substrate 120 a may be formed byremoving a center portion of the lower passivation layer 123 d. Thefirst trench T1 and the second trench T2 may each have an area whichenables the first semiconductor chip 130 to be accommodated thereinto.

In the semiconductor package 100 g according to the present embodiment,the second upper passivation layer 113 u-2 a may perform a function of agap filler. For example, the second upper passivation layer 113 u-2 amay be referred to as a gap filler. Therefore, as illustrated in FIG.8B, the second upper passivation layer 113 u-2 a may have a rectangularstructure which is long in a second direction (e.g., a y direction), onthe first upper passivation layer 113 u-1 a. According to embodiments,the first upper passivation layer 113 u-1 a of the first packagesubstrate 110 c may have substantially the same thickness as that of theupper passivation layer 113 u of the first package substrate 110 of thesemiconductor package 100 of FIG. 1, and the second upper passivationlayer 113 u-2 a may have substantially the same thickness as that of thegap filler 150 of the semiconductor package 100 of FIG. 1.

FIGS. 9A to 9C are plan views illustrating various embodiments of astructure of a gap filler, in one of the semiconductor packages of FIGS.6A, 7A, and 8A. Descriptions, which are the same as or similar todescriptions given above with reference to FIGS. 6A to 8B, are brieflygiven below or omitted.

Referring to FIG. 9A, in a structure of a second upper passivation layer113 u-2 b or a second lower passivation layer, a semiconductor package100 h according to the present embodiment may differ from thesemiconductor package 100 e of FIG. 6A. For example, in thesemiconductor package 100 h according to the present embodiment, a widthin a first direction (e.g., an x direction) of opposite end portions ofthe second upper passivation layer 113 u-2 b in a second direction(e.g., a y direction) may be greater than a width of another portionthereof. For example, the second upper passivation layer 113 u-2 b mayhave a ‘[’-shape. Based on such a structure of the second upperpassivation layer 113 u-2 b, in a portion corresponding to an injectionpath IP, a gap between second upper passivation layers 113 u-2 b in thefirst direction (e.g., the x direction) may be narrower than a width ofa first trench T1 in the first direction (e.g., the x direction). Awidth of the second upper passivation layer 113 u-2 b at the oppositeend portions thereof in the second direction (e.g., the y direction) maybe greater than a width of the second upper passivation layer 113 u-2 bat the central portions in the second direction, and thus, the secondupper passivation layer 113 u-2 b may surround and protect more firstconnection members 140, thereby decreasing defects such as a shortcircuit, solder deformation, and non-wetting of the first connectionmembers 140.

Referring to FIG. 9B, in a structure of a second upper passivation layer113 u-2 c or a second lower passivation layer, a semiconductor package100 i according to the present embodiment may differ from thesemiconductor package 100 e of FIG. 6A. For example, in thesemiconductor package 100 i according to the present embodiment, a widthin a first direction (e.g., an x direction) at one end portion of thesecond upper passivation layer 113 u-2 c in a second direction (e.g., ay direction) may be greater than a width of another portion thereof inthe second direction. For example, the second upper passivation layer113 u-2 c may have a ‘L’-shape. Based on such a structure of the secondupper passivation layer 113 u-2 c, in a portion corresponding to aninjection path IP, a gap between second upper passivation layers 113 u-2c in the first direction (e.g., the x direction) at the one end portionof the second upper passivation layer 113 u-2 c may be narrower than awidth of a first trench T1 in the first direction (e.g., the xdirection) at another portion. A width of the second upper passivationlayer 113 u-2 c at the one end portion thereof (for example, an endportion corresponding to the injection path IP) in the second direction(the y direction) may be greater than a width of the second upperpassivation layer 113 u-2 c at another portion, and thus, the secondupper passivation layer 113 u-2 c may surround and protect more firstconnection members 140, thereby decreasing defects such as a shortcircuit, solder deformation, and non-wetting of the first connectionmembers 140.

Referring to FIG. 9C, in a structure of a second upper passivation layer113 u-2 d or a second lower passivation layer, a semiconductor package100 j according to the present embodiment may differ from thesemiconductor package 100 e of FIG. 6A. For example, in thesemiconductor package 100 j according to the present embodiment, thesecond upper passivation layer 113 u-2 d may be disposed on a firstupper passivation layer 113 u-1 of a first package substrate 110 atopposite sides of a first semiconductor chip 130 or a first trench T1 ina first direction (an x direction), and may be disposed in a latticeshape between a plurality of first connection members 140. For example,it may be seen that the first connection members 140 are disposedbetween adjacent portions of the second upper passivation layer 113 u-2d having a lattice shape. As illustrated, the second upper passivationlayer 113 u-2 d may not be disposed at a portion corresponding to aninjection path IP. In a process of stacking the second package substrate120 and a process of injecting a first sealant 136, the second upperpassivation layer 113 u-2 d having a lattice shape may surround andprotect the first connection members 140, thereby preventing defectssuch as a short circuit, solder deformation, and non-wetting of thefirst connection members 140.

FIG. 10 is a cross-sectional view of a semiconductor package 200 havinga PoP structure according to an embodiment. Descriptions, which are thesame as or similar to descriptions given above with reference to FIGS. 1to 3B, are briefly given below or omitted.

Referring to FIG. 10, the semiconductor package 200 according to thepresent embodiment may include a first redistribution wiring layer 210and a second redistribution wiring layer 220, instead of a first packagesubstrate 110 and a second package substrate 120, and may also includetwo upper packages 260 and 270 and a passive element 280, and thus, maydiffer from the semiconductor package 100 of FIG. 1. For example, thesemiconductor package 200 according to the present embodiment mayinclude the first redistribution wiring layer 210, the secondredistribution wiring layer 220, a first semiconductor chip 230, a firstconnection member 240, a gap filler 250, first and second upper packages260 and 270, the passive element 280, and a second sealant 290.

The first redistribution wiring layer 210 may be disposed under thefirst semiconductor chip 230, and chip pads of the first semiconductorchip 230 may be redistributed in an outer region of the firstsemiconductor chip 230 through the first redistribution wiring layer210. For example, the first redistribution wiring layer 210 may connectthe chip pads of the first semiconductor chip 230 to an outer connectionpad on a bottom surface of the first redistribution wiring layer 210through a redistribution wiring, and thus, may rearrange the chip padsof the first semiconductor chip 230 on an area which is greater than thefirst semiconductor chip 230. The first redistribution wiring layer 210may include a first body layer 211 including or being formed of aninsulating material such as a photo imageable dielectric (PID) resin, anupper passivation layer 213 u on a top surface of the first body layer211, and a lower passivation layer 213 d on a bottom surface of thefirst body layer 211. A redistribution wiring having a single-layer ormulti-layer structure may be disposed in the first body layer 211. Thefirst redistribution wiring layer 210 may include a first trench T1which is formed by removing a center portion of the upper passivationlayer 213 u.

An outer connection member 215 may be disposed on a bottom surface ofthe first redistribution wiring layer 210. As illustrated in FIG. 10,the outer connection member 215 may be disposed on a first portion,corresponding to a bottom surface of the first semiconductor chip 230,and a second portion which is the outside of the first portion in afirst direction (e.g., an x direction) and a second direction (e.g., a ydirection). A package structure, where the outer connection member 215is widely disposed outside a bottom surface of the first semiconductorchip 230, may be referred to as a fan-out (FO) package structure. On theother hand, a package structure where an outer connection member isdisposed on only a portion corresponding to a bottom surface of a firstsemiconductor chip, may be referred to as a fan-in (FI) packagestructure.

The second redistribution wiring layer 220 may be disposed on the firstredistribution wiring layer 210 and the first semiconductor chip 230.The second redistribution wiring layer 220 may be electrically connectedto the first redistribution wiring layer 210 through the firstconnection member 240. The second redistribution wiring layer 220 mayinclude a second body layer 221, an upper passivation layer 223 u, and alower passivation layer 223 d. The second redistribution wiring layer220 may include a second trench T2 which is formed by removing a centerportion of the lower passivation layer 223 d. A material or a structureof the second redistribution wiring layer 220 may be substantially thesame as that of the first redistribution wiring layer 210.

The first semiconductor chip 230 may be mounted in the first trench T1of the first redistribution wiring layer 210. In some embodiments, thefirst semiconductor chip 230 may be mounted on a region of the firstredistribution wiring layer 210 wherein the first trench T1 is formed.The first semiconductor chip 230 may correspond to the firstsemiconductor chip 130 of the semiconductor package 100 of FIG. 1. Thefirst semiconductor chip 230 may be mounted on the first redistributionwiring layer 210 through a second connection member 232 and an underfill234 and may be sealed by a first sealant 236. According to embodiments,the first semiconductor chip 230 may have a structure where a chip padis directly connected to a redistribution wiring of the firstredistribution wiring layer 210 without the second connection member232. For reference, a structure where the first redistribution wiringlayer 210 is first formed and the first semiconductor chip 230 ismounted on the first redistribution wiring layer 210 through the secondconnection member 232 may be referred to as a chip last structure, and astructure where the first redistribution wiring layer 210 is formed onthe first semiconductor chip 230 may be referred to as a chip firststructure. A package structure including the first redistribution wiringlayer 210 may be referred to as a wafer level package (WLP), and apackage structure which includes a fan-out structure through the firstredistribution wiring layer 210 may be referred to an FO-WLP.

The first connection member 240 may have a shape such as a through viaas illustrated. However, a structure of the first connection member 240is not limited thereto. For example, like the semiconductor package 100of FIG. 1, the first connection member 240 may have a structureincluding a pillar and a solder, or like the semiconductor package 100 dof FIG. 5, the first connection member 240 may have a structureincluding only a solder.

The gap filler 250 may correspond to the gap filler 150 of the firstsemiconductor package 100 of FIG. 1. Therefore, the gap filler 250 mayinclude or may be formed of a material (for example, NCF, NCP, or SR)which differs from that of the first sealant 236 and may fill aplurality of first connection members 240 disposed between the firstredistribution wiring layer 210 and the second redistribution wiringlayer 220 outside the first semiconductor chip 230. The gap filler 250may have a rectangular shape which is long in a second direction (e.g.,a y direction). However, the gap filler 250 is not limited thereto andmay have a shape of one of the gap fillers 150 a to 150 c of FIGS. 4A to4C.

The first sealant 236 may correspond to the first sealant 136 of thefirst semiconductor package 100 of FIG. 1. The first upper package 260may be mounted on the second redistribution wiring layer 220 through athird connection member 262. The first upper package 260 may correspondto, for example, the upper package 160 of the first semiconductorpackage 100 of FIG. 1. Therefore, the first upper package 260 mayinclude at least one second semiconductor chip, and the secondsemiconductor chip may include, for example, a DRAM chip. However, thesecond semiconductor chip is not limited to the DRAM chip.

The second upper package 270 may be mounted on the second redistributionwiring layer 220 through a fourth connection member 272. The secondupper package 270 may include at least one third semiconductor chip. Thethird semiconductor chip may include a memory chip which differs fromthe second semiconductor chip. The third semiconductor chip may include,for example, an SRAM chip or a flash memory chip. However, the thirdsemiconductor chip is not limited to the SRAM chip or the flash memorychip.

Although not shown, an underfill surrounding the third connection member262 may be disposed between the first upper package 260 and the secondredistribution wiring layer 220. An underfill surrounding the fourthconnection member 272 may be disposed between the second upper package270 and the second redistribution wiring layer 220. However, in a casewhere a second sealant 290 is formed through an MUF process, anunderfill may be omitted.

The passive element 280 may be mounted on the second redistributionwiring layer 220. The passive element 280 may include, for example, atwo-terminal element such as a resistor element, an inductor element, ora capacitor element. The second sealant 290 may seal the first andsecond upper packages 260 and 270 and the passive element 280 on thesecond redistribution wiring layer 220. The second sealant 290 may beformed of EMC like the second sealant 169 of the semiconductor package100 of FIG. 1. However, a material of the second sealant 290 is notlimited to the EMC.

In the semiconductor package 200 according to the present embodiment,the first semiconductor chip 230 may be disposed between the first andsecond trenches T1 and T2 formed in the first and second redistributionwiring layers 210 and 220, and the gap filler 250 including a materialwhich differs from that of the first sealant 236 may surround the firstconnection member 240 between the first and second redistribution wiringlayers 210 and 220, whereby a fine pitch of the first connection member240 may be implemented and a total height of a package may decrease. Inthe semiconductor package 200 according to the present embodiment, adefect such as a short circuit, solder deformation, or non-wetting inthe first connection member 240 may be prevented by the gap filler 250.Accordingly, a semiconductor package having a PoP structure withenhanced reliability may be implemented.

FIGS. 11A to 17 are cross-sectional views illustrating a method ofmanufacturing a semiconductor package having a PoP structure, accordingto an embodiment. The method of manufacturing a semiconductor packagehaving a PoP structure according to an embodiment will be describedbelow with reference to FIGS. 11A to 17 in conjunction with FIGS. 1 to3B, and descriptions, which are the same as or similar to descriptionsgiven above with reference to FIGS. 1 to 3B, are briefly given below oromitted.

Referring to FIGS. 11A and 11B, the method of manufacturing asemiconductor package having a PoP structure according to an embodimentmay include an operation of preparing a first package substrate 110 anda second package substrate 120, an operation of forming a first trenchT1 in the first package substrate 110, and an operation of forming asecond trench T2 in the second package substrate 120. The first packagesubstrate 110 and the second package substrate 120 may be the same asthe first package substrate 110 and the second package substrate 120 ofthe semiconductor package 100 of FIG. 1 described above.

The first trench T1 and the second trench T2 may be formed through aphotolithography process using a photomask 500 as illustrated in FIG.11B. For example, an exposure process using the photomask 500 includingan open region OA corresponding to the first and second trenches T1 andT2 may be performed on passivation layers 113 and 123 of the first andsecond package substrates 110 and 120, and by removing an exposed regionthrough a development process using a developer, the first and secondtrenches T1 and T2 may be formed in the first and second packagesubstrates 110 and 120.

Referring to FIG. 12, a first pillar 141 may be formed on a top surfaceof the first package substrate 110, and a second pillar 143 and a solder145 may be formed on a bottom surface of the second package substrate120. As seen in FIG. 2C, the first pillar 141 may be formed at a portionof an upper passivation layer 113 u outside the first trench T1. Thesecond pillar 143 and the solder 145 may be formed at a portion of alower passivation layer 123 d outside the second trench T2. According toembodiments, a solder may be formed on the first pillar 141 instead ofbeing formed on the second pillar 143.

Referring to FIG. 13, a first semiconductor chip 130 may be mounted inthe first trench T1 of a top surface of the first package substrate 110.For example, the first semiconductor chip 130 may be mounted on a regionof the first package substrate 110 where the first trench T1 is formed.The first semiconductor chip 130 may be mounted on the first packagesubstrate 110 through a third connection member 132 and an underfill134. As described above, in a case where a first sealant 136 is formedthrough an MUF process, the underfill 134 may be omitted. The firstsemiconductor chip 130 may be the same as the first semiconductor chip130 of the semiconductor package 100 of FIG. 1 described above.

Referring to FIG. 14, a gap filler 150 may be formed at a portion of anupper passivation layer 113 u of the top surface of the first packagesubstrate 110. The gap filler 150, as illustrated in FIG. 3A, may have arectangular shape which is long in a second direction (e.g., a ydirection). However, the gap filler 150 is not limited thereto and mayhave a shape of one of the gap fillers 150 a to 150 c of FIGS. 4A to 4C.

The gap filler 150 may be formed to cover the first pillar 141 disposedin the upper passivation layer 113 u. The gap filler 150 may be formedon the second package substrate 120 instead of the first packagesubstrate 110. In this case, the gap filler 150 may be formed on a lowerpassivation layer 123 d of the second package substrate 120 and may beformed to cover the second pillar 143 and the solder 145 each disposedin the lower passivation layer 123 d.

Referring to FIG. 15, the second package substrate 120 may be stacked onthe first package substrate 110 through a TCB process. The first pillar141 and the second pillar 143 may be coupled to each other through thesolder 145 by stacking the second package substrate 120 on the firstpackage substrate 110 to form a first connection member 140. Forexample, the first connection member 140 may include the first pillar141, the second pillar 142, and the solder 145 disposed therebetween. Asdescribed above, the flow of the solder 145 may be minimized by the gapfiller 150 in the TCB process, thereby preventing defects such as ashort circuit, solder deformation, and non-wetting.

Referring to FIG. 16, the first semiconductor chip 130 may be sealed byinjecting the first sealant 136 (for example, an EMC) through aninjection path IP (see, FIGS. 3A and 3B). The first sealant 136 may fillthe first and second trenches T1 and T2 and may cover a top surface anda side surface of the first semiconductor chip 130 and the underfill134. As described above, the gap filler 150 may prevent the firstsealant 136 from penetrating (i.e., flowing into) spaces between thefirst connection members 140 in a process of injecting the first sealant136, thereby preventing defects such as a short circuit, solderdeformation, and non-wetting from occurring in the first connectionmembers 140.

Referring to FIG. 17, an upper package 160 may be mounted on a secondpackage substrate 120 through a second connection member 162. The upperpackage 160 may be the same as the upper package 160 of thesemiconductor package 100 of FIG. 1 described above. Subsequently, anexternal connection member 115 may be disposed on a bottom surface ofthe first package substrate 110, and thus, the semiconductor package 100of FIG. 1 may be finished.

While the inventive concept has been particularly shown and describedwith reference to embodiments thereof, it will be understood thatvarious changes in form and details may be made therein withoutdeparting from the spirit and scope of the following claims.

1. A semiconductor device having a package on package (PoP) structurecomprising: a first package substrate including a first body layer and afirst passivation layer on a top surface of the first body layer; afirst semiconductor chip mounted on the first package substrate; asecond package substrate disposed on the first package substrate and thefirst semiconductor chip, the second package substrate including asecond body layer and a second passivation layer on a bottom surface ofthe second body layer; a plurality of first connection members disposedon the first package substrate outside the first semiconductor chip toelectrically connect the first package substrate to the second packagesubstrate; and a gap filler filled between the first package substrateand the second package substrate and surrounding at least some ofportions of the plurality of first connection members, wherein the firstpackage substrate comprises a first trench formed by removing a centerportion of the first passivation layer, wherein the second packagesubstrate comprises a second trench formed by removing a center portionof the second passivation layer, and wherein the first semiconductorchip is disposed in a space between the first trench and the secondtrench.
 2. The semiconductor device of claim 1, further comprising: anepoxy molding compound (EMC) filling at least a portion of each of thefirst trench and the second trench and covering the first semiconductorchip, wherein the gap filler comprises a material which differs from theEMC.
 3. The semiconductor device of claim 1, wherein each of theplurality of first connection members comprises: a first pillarconnected to the first package substrate; a second pillar connected tothe second package substrate; and a solder connecting the first pillarto the second pillar.
 4. The semiconductor device of claim 1, whereineach of the plurality of first connection members comprises: a solderball directly connecting the first package substrate to the secondpackage substrate.
 5. The semiconductor device of claim 1, wherein thegap filler comprises one of a nonconductive film (NCF), a nonconductivepaste (NCP), and solder resist (SR).
 6. The semiconductor device ofclaim 1, wherein the first passivation layer and the second passivationlayer comprise solder resist (SR), and wherein each of the firstpassivation layer and the second passivation layer is formed in a singlelayer.
 7. The semiconductor device of claim 1, wherein the firstpassivation layer and the second passivation layer comprise solderresist (SR), wherein each of the first passivation layer and the secondpassivation layer is formed in a multi-layer structure, and wherein eachof the first trench and the second trench is formed by removing all ofthe multi-layer structure or is formed by removing a portion of themulti-layer structure.
 8. The semiconductor device of claim 1, whereinthe gap filler is disposed at opposite sides of the first semiconductorchip in a first direction and has a shape which extends in a seconddirection vertical to the first direction.
 9. The semiconductor deviceof claim 8, wherein the gap filler has one shape of a first shape of arectangle, a second shape where a width in the first direction atopposite end portions in the second direction is greater than a width ofanother portion, a third shape where a width in the first direction atone end portion in the second direction is greater than a width ofanother portion, and a fourth shape of a lattice shape defining aplurality of spaces in which the plurality of first connection membersare disposed.
 10. The semiconductor device of claim 1, wherein the gapfiller is configured to maintain a first gap between the firstsemiconductor chip and the second package substrate, and wherein thefirst gap is filled with an epoxy molding compound (EMC).
 11. Thesemiconductor device of claim 1, further comprising: an upper packagemounted on the second package substrate, wherein the upper packagecomprises an upper substrate and a second semiconductor chip mounted onthe upper substrate.
 12. The semiconductor device of claim 11, whereinthe second package substrate comprises a silicon interposer, a panelinterposer, or a glass interposer, wherein the first semiconductor chipcomprises a logic chip, wherein the second semiconductor chip comprisesa memory chip, and wherein the upper package further comprises a thirdsemiconductor chip which is stacked on the second semiconductor chip.13. A semiconductor device having a package on package (PoP) structurecomprising: a first package substrate including a first body layer, afirst upper passivation layer on a top surface of the first body layer,and a first lower passivation layer on a bottom surface of the firstbody layer, and a first trench formed at a center portion of the firstupper passivation layer on the top surface of the first body layer; asecond package substrate disposed on the first package substrate, thesecond package substrate including a second body layer, a second upperpassivation layer on a top surface of the second body layer, and asecond lower passivation layer on a bottom surface of the second bodylayer, and a second trench formed at a center portion of the secondlower passivation layer on the bottom surface of the second body layer;a first semiconductor chip mounted on a top surface of the first packagesubstrate and disposed in a space between a first region of the firstpackage substrate where the first trench is formed and a second regionof the second package substrate where the second trench is formed; anupper package mounted on a top surface of the second package substrate,the upper package including a second semiconductor chip; an epoxymolding compound (EMC) covering the first semiconductor chip and fillingat least a portion of each of the first trench and the second trench;and a gap filler including a material which differs from the EMC andfilling at least a portion between the first upper passivation layer ofthe first package substrate and the second lower passivation layer ofthe second package substrate.
 14. The semiconductor device of claim 13,further comprising: a first connection member disposed on the firstpackage substrate outside the first semiconductor chip to electricallyconnect the first package substrate to the second package substrate,wherein the first connection member comprises a first pillar connectedto the first package substrate, a second pillar connected to the secondpackage substrate, and a fine solder connecting the first pillar to thesecond pillar.
 15. The semiconductor device of claim 13, furthercomprising: a plurality of first connection members disposed on thefirst package substrate outside the first semiconductor chip toelectrically connect the first package substrate to the second packagesubstrate, wherein the gap filler comprises one of a nonconductive film(NCF), a nonconductive paste (NCP), and solder resist (SR) and surroundsat least some of portions of the plurality of first connection members.16. The semiconductor device of claim 13, wherein each of the firstupper passivation layer, the first lower passivation layer, the secondupper passivation layer, and the second lower passivation layercomprises solder resist (SR), and is formed in a single layer ormulti-layer structure.
 17. The semiconductor device of claim 13, furthercomprising: a plurality of first connection members disposed on thefirst package substrate outside the first semiconductor chip toelectrically connect the first package substrate to the second packagesubstrate, wherein the gap filler is disposed at opposite sides of thefirst semiconductor chip in a first direction and extends in a seconddirection vertical to the first direction, and wherein the gap fillerhas one shape of a first shape of a rectangle, a second shape where awidth in the first direction at opposite end portions in the seconddirection is greater than a width of another portion, a third shapewhere a width in the first direction at one end portion in the seconddirection is greater than a width of another portion, and a fourth shapeof a lattice shape defining a plurality of spaces in which a pluralityof first connection members are disposed.
 18. The semiconductor deviceof claim 13, wherein the upper package further comprises: an uppersubstrate on which the second semiconductor chip is mounted; a sealantsealing the second semiconductor chip; and a third semiconductor chipmounted on the upper substrate, and wherein the second and thirdsemiconductor chips are stacked on each other.
 19. The semiconductordevice of claim 13, wherein the first trench and the second trench areconfigured to accommodate the first semiconductor chip to reduce athickness of the semiconductor device. 20.-28. (canceled)